In the related art, an image processing apparatus is known which is mounted in a vehicle such as an automobile, detects a raindrop and monitors surroundings of the vehicle. In such an image processing apparatus, an image pickup unit that takes an image is mounted.
For example, there is an image processing apparatus that includes a lens that can have a first focal length for a short distance for taking an image of a raindrop that has adhered to a vehicle and a second focal length for a long distance for taking an image of surroundings of the vehicle; a camera part that switches between the first focal length and the second focal length; a raindrop detection part that detects whether there is a raindrop based on an image taken by the camera part with the first focal length; and a monitoring part that monitors surroundings of the vehicle based on an image taken by the camera part with the second focal length. In this image processing apparatus, the camera part corresponds to an image pickup unit (for example, see Japanese Laid-Open Patent Application No. 2005-225250 (Patent Reference No. 1)).
However, the image pickup unit (camera part) of the Patent Reference No. 1 uses the bifocal lens, focuses the lens on a raindrop when detecting the raindrop that has adhered to the windshield surface and focuses the lens on surroundings of the vehicle when detecting the vehicle surrounding information. Thus, when a raindrop is detected while the lens is focused on a windshield surface, it may be difficult to extract an area of the raindrop because the contrast between the raindrop and the background may be included in an image of the raindrop and also a position of a bright spot may be moved according to a position of a light source.
That is, according to the image pickup unit (camera part) of the Patent Reference No. 1, it may be difficult to take an image of a raindrop that has adhered to a windshield surface and vehicle surrounding information that is far from the position of the windshield in the respective suitable conditions.